Collisions with obstacles such as suspended wires and point obstacles such as pylons account for a large percentage of severe and fatal helicopter and other aircraft accidents, especially, but not only during bad visibility conditions and adverse weather. The need for a device that would provide adequate warning against such obstacles is well known for aircraft which are required to fly low. These include, but are not limited to, medical evacuation (MEDEVAC), search and rescue (S&R) and police helicopters. Other categories of aircraft which require obstacle detection and warning include unmanned air vehicles (UAVs), and transport aircraft.
Prior art sensor systems apparently do not detect wires effectively. These include, for example, millimetric wave radar, laser radar, FLIR and more. These prior art systems are complex, heavy and costly and only achieve a limited success in detecting wires.
PCT patent application publication serial number WO/2013/164811A discloses a system for detecting wires using polarized waves. Basically, this system includes a transmitter for transmitting multi-polarized waves, means for receiving waves reflected off target and means for analyzing the polarization of the reflected waves to detect linearly polarized echoes characteristic of wires.